I see: "4 year old twin girls."
You didn't mention their ages, but I sympathize with your situation, as it sounds like you've tried most everything that comes to mind for discipline. You could try to step it up a notch and give them extended bare bottom spankings in front of the boys, using open palm and not hard enough to bruise, of course. I've seen a couple of cases in my extended family where this has worked due to the effect of embarrassment. You just have to spank long enough so the child doesn't think of it as a quick bump in the road.